The invention relates to a method for producing a semiconductor device from a composite board with semiconductor chips. The composite board also has a plastic housing composition besides the semiconductor chips.
“Embedded dye” technologies, in which one or even a plurality of semiconductor chips are surrounded with a plastic housing by techniques such as encapsulation by molding, encapsulation by lamination or layer-by-layer construction of the plastic, have numerous advantages over conventional technologies in which the semiconductor chip is applied to a substrate by contacts, such as solder balls, and is subsequently surrounded with a plastic housing. Thus, they permit smaller and lighter devices, by way of example, and enable the fixed connection of a plurality of chips in a single housing and also a higher density of electrical connections.
Moreover, the “embedded dye” technologies afford advantages in production. DE 10 2005 026 098, not published before the priority date, discloses a semiconductor device whose production involves the processing of semiconductor chips by encapsulation by molding into a plastic composition to form a composite board, the active top sides of the semiconductor chips together with the top side of the composite board forming a coplanar area, while their edges and the rear side are covered by the plastic housing composition. A wiring structure with conductor tracks insulated from one another by dielectric layers can be applied to the coplanar area particularly well and precisely.
However, there is the risk of the occurrence of warpage of the composite board caused by the different coefficients of thermal expansion of the materials, leading to locally different degrees of shrinkage of the plastic housing composition during curing and hence to a distortion and warpage of the composite board.
Whereas planar composite boards, which can have the form and dimensions of standard wafers, have the advantage that they can be processed further by standard processes and automatic machines established for wafers, warped composite boards do not have this advantage. On account of their warpage, typically they cannot be processed further or warpage has to be corrected by complicated carrier systems and/or complex aftertreatments such as loading by weights during curing and in all of the following process steps which are accompanied by temperature loadings, that is to say heat up the composite board and/or cool it down again. However, this procedure is extremely complex and therefore cost-intensive. Consequently, the economic advantage actually entailed by the production of semiconductor devices from the composite board cannot be exploited.